Depolarizing battery-electrode and process of making same



.3370 Drawing. I

UNHT

STATES.

PATENT 'OFFICE.

HAYIKGND G. BENNEE- AND'HAR-RY'F. FRENCH, BF FREMONT, OHIO, ASSIGNORS 'IO INTA'IIOI WA L CARBON COMPANY, INC., A CORPORATION OF NEW YORK;

DEEOLARIZING BATTERY-ELECTRODE AND PROCESS OF MAKING- SAME.

itknown thative, RAYMOND C. BENNER and HAR Y F. FRENCH, citizens of the United States, and residents of Fremont, in

the ounty of Sandusky. and State of Ohio, ha'veunvented a certain new and useful lniprovement in Depolarizling Battery-Eleotrodes and Processes of hllaking Same, of which thedollowi11g is-a full, clear, and exact descriptioi'l.

' This invention relates to a process of prepa ug jdepolarizers for electric batteries and more particularly to copper oxid depolarizers used in the zinc alkaline type of cell.

It has been found that the voltage of the copper oxid cell of the type referred to canbe materially increased by'adding sulfur, sulfide or other sulfur-containing material as describedin the patent of Raymond W. Erwin patented. Oct. 22, 1918 No. 1,28%;957, and in our copending application filedilan, 26, 1917', Serial No. 144,618. We have-found that the voltage raise, due to the sulfur or sulfur-containing material, can be increased. by a special process of preparing the depolarizer. This process, which is in part an electrolytic one, will now be described.

We use an electrolyte of sodium chlorid with copper electrodes, and pass a current through. the electrolytic cell to precipltate cuprous oxid (C11 9) at the cathode.

The concentration of the sodium chlorid electrolyte and the current density can be been obtained it is taken out and Washed substantially free of sodium chlorid solution and is then oxidized in the air to cupric oxid. We have tried various temperatures of reoxidizing the cuprous said, from room temperature up to 8Y5 (3., all of wh ch are suc essliul as far as the final product is concerned. At room temperatures, however, the oxidation is too slow to be practically satis factory unless moistened with y ater 01- eodium hydroxid solution. The higher the Specification of Letters Patent.

Application filed August 22, 1918. Serial No. 255L029.

temperature of oxidation, the less is the advantage in adding the solution, until finally. at a temperature of 700 to 875 (1, nomoistoning with Water or sodium hydroxid is necessary. 7

After the electrolytically prepared cuprous oxid has been oxidized to cupric oXid, from 1 to 3% sulfur is added to produce the lugh voltage effect previously referred to. Preferably the mixture is stirred and heated su'liiciently to melt the sulfur and cause it to adhere to the oxid particles.

, l Vhen a depolarizer has been prepared in this Way and placed in a cell consisting of a perforated tinned iron container in a sodium l'iydroxid electrolyte with a zinc electrode, the average Voltage throughout the life of the cell is about l l% higher than the voltage produced in a cell having; commercial scale oxid mixed With sulfur or sulfur material, the life being computed on one ampere continuous test down to .5 volt. Since the ordinary cupric oxid, when mixed with sulfur or sulfurinaterial, asdescribed inthe prior appli cations referred to, produces a very substantial increase in voltage over the ordinary copper oxid cell, it will be apparent that our improved process forming a battery depolarizer is of great commercial importance.

It has also been found that When a bat tery is made of ordinary commercial cupric oxid and sulfur the voltage fluctuates at low atmospheric temperatures. With the depolarizer made by our improved process the criti al temperature at which fluctuation in voltage is liable to commence is lowered over 0., for some reason that at present is not known, the critical temperature of the improved depolarizer being in the neighbon hood of l" C. Inasmuch as the copper oxid type of cell, which chiefly used in railway Work, is rarely subjected to a temperature below 0 C. in practice, it ivill be evident that the depolarizer made by the improved process is of decided commercial importance.

It will be understood that various changes may be made in our process Without departing from the spirit of the inyention. For instance, the sulfur may be m xed with the cuprous oxid before the air oxidation, 11 the temperature isnot raised much above 200 0. Above 250 C. the sulfur or sulfur material should be added after the oxidation,

to prevent the chemical combination he-' tween the two materials forthe formation of sulfate or the reduction oi: the cuprous GXHl to metallic copper with the formation of fur material and used in a copper oxid type,

of cell. 'The electrolytic formation of cuprous oxid, however, has she advantage over the CllPllC 02nd process by virtue of the fact that it moves twice as much copper per amperehour.

Various amounts of: sulfur 0r sulfur material may be mixed with the cupric oxid to produce the high voltage effect, as mentioned in the prior applications above referred to, hot a satisfactory average proportion 1.2%.

Having described our invention, what We claim is: a y

l. The process of preparing a high volt age depolarizei. for electric batteries, which consists in oxidizing copper by electrolysis sndmixing sulfurwith the resulting oxid.

2. The process of preparing a high volt age depolarizer for electric batteries, which. consists in producing cliprous oxid Toy electrolysis, oxidizing the cuprous oxirl to cupric oxid and addiiigsulfur.

3. A depolarizing electrode for electric for practical purposes will be about 1 batteries containing an oxidized copper compound derived from (mid, and sulfur.

In testimony whereof, We hereunto afiix our signatures. 1

RAYMOND C. BENNER. HARRY F. FRENCH.

electrolytic cuprous 

